1. Field of the Invention
The present invention relates to an adaptor serving for both a mobile phone unit and a private IP (Internet protocol) telephone of which the mobile phone unit can be used as the private IP telephone unit.
2. Description of the Related Art
In recent years, a private IP telephone unit that uses a LAN (local area network) as a private telephone network circuit, which spreads over premises, is known.
A sales person who mainly works in a suburb area often uses a mobile phone unit. When he or she goes back to his or her office, he or she uses a private IP telephone unit. In this case, since the telephone number of the mobile phone unit is different from the telephone number of the private IP telephone unit, when someone wants to urgently contact the sales person, the calling party should call him or her with the suitable telephone number of the mobile phone unit or the private telephone unit.
In addition, a technology of which a mobile phone unit has a function for an IP telephone has been disclosed (for example, refer to Related Art Reference 1).